I'm not sure if I completely understand your question, partially because the regexps are obscured since code tags weren't used to preserve things like []. And partially because the text that came between "Now the question is this:" and the question mark, didn't really make sense to me.

From what I can tell, it looks to me like in the first regexp, you're only capturing with one set of parens. That means that $1 is the only variable that will have anything captured into it, in your first regexp. Nothing is populating $2 and $3. Also, $1 will only have something captured into it if the overall match was a success. Also, there is no need to use square brackets around \W if you're only matching one character, with a built-in character class. The square brackets are generally used to create custom character classes.

I hope this is of some help.

If your book gave you the regexp you have shown us, it would be a good candidate for the garbage heap. You might really get a lot out of perlretut, followed by perlfaq6, followed by perlre. Those three online POD's give a very thorough explanation of regular expressions, and start out (in perlretut) at a pace that isn't too overwhelming.

As far as what $1 $2 and $3 would "obviously" contain, I have no idea because you didn't provide the actual input string for us to see.

Your second regexp (the one that follows "THIS should work:" will substitute the first non-word character in the string with a hyphen. Is that what you meant by "work"? I might be missing something too. ;)


Dave


"If I had my life to do over again, I'd be a plumber." -- Albert Einstein

In reply to Re: String Substitution Operator by davido
in thread String Substitution Operator by hehenoobhehe

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